Cell culture microscopes for observing changes in state while cultivating live cells, and observation devices for observing road or maritime traffic congestion conditions and the like, are types of apparatuses such as the one described above for using a time-lapse image to observe changes in an observed object. In an apparatus of such description, taking a cell culture microscope as an example, in order to observe the motion states of individual cells or between cells and perform an appropriate evaluation, it is necessary to verify the spatial position of each cell in a field of view using hardware or software means and generate a time-lapse image.
In order to verify the spatial position of each of the cells in the field of view, i.e., the relative positions of the observed object and the observation optical system that includes the imaging device, by hardware means using a mechanism configuration, it is necessary to provide an alignment optical system for positional correction or use Super Invar, a ceramic, or another costly material having an extremely low thermal expansion coefficient to constitute the members in order to minimize the effects of temperature drift; so that the entire apparatus increases in complexity and cost. Also, in order to minimize the relative positional shift between the observation optical system and the observed object, it is necessary to fix the relative positions of the observation optical system and the observed object and to continue observing the same observed object. In order to avoid such disadvantages and make it possible to observe a plurality of observed objects while exchanging the observed objects as appropriate, there has been proposed a method for correlating intermittently captured images as a whole, whereby positional correction between images is performed by software means (see e.g., patent document 1).    Patent Document: 1 Japanese Laid-open Patent Application No. 2006-23494